It's difficult to tell from the photos, but these teacups have a wonderful graduated shape: their top diameter is 3 1/4" while the bottom diameter is 3 1/2".

 

This set of four restaurant ware cups by Jackson China features dark red or maroon sides with white handle, interior and bottom. Date code is 1951. Being stackable, unfortunately there is some stacking wear on the tops of two of the cups.

 

Price is for all four cups.